Late Relapse in Hodgkin Lymphoma (HL): A Retrospective Analysis of Patients Enrolled on Clinical Trials at the Istituto Nazionale Tumori of Milan (INT-MI)

Background The majority of relapses in HL occur within the first three years from end of first-line treatment. Late relapses, occurring after more than five years, are rare events and there is no consensus on the optimal treatment.

Aims of study The aim of our retrospective analysis was to assess the proportion of relapses occuring > 5 years in patients enrolled on clinical trials at INT-MI between 1974 and 2007, to evaluate prognostic factors, treatment outcome and survival.

Patients and Methods  From 1974 to 2007, 1089 consecutive HL patients, previously untreated with chemotherapy (CT), were enrolled on clinical trials at the INT-MI; 959 patients in complete remission (CR) after first-line CT or combined modality treatment were included in this study. In all patients who relapsed >5 years from end of frontline treatment a second biopsy was performed to prove HL histology at relapse. Failure-free survival (FFS) was calculated from the date of late relapse until documented relapse from CR after salvage therapy, disease progression during or within 3 months from end of salvage therapy, or death, whichever came first. Overall survival (OS) was calculated from the date of late relapse to last follow-up visit or death.

Results A total of 31 complete responders after first-line therapy relapsed after > 5 years. Median time from end of first-line therapy to relapse was 115 months (range, 63-299). Main patient characteristics at late relapse were as follows: males: 71%; median age: 48 years (range, 20-67); classical histology: 81%; stage III/IV: 55%; B Symptoms: 48%; extranodal disease: 26%; > 3 involved sites: 52%; bulky disease: 13%; GHSG prognostic score ³ 1: 52%; MSKCC prognostic score ³ 1: 61%. Conventional dose salvage chemotherapy (CT) was delivered to 64.5% of patients: 9 patients were retreated with the same regimen employed as front-line therapy (MOPP alternated with ABVD), 5 were retreated with ABVD alone, 6 received non cross-resistant regimens. High-dose chemotherapy (HDCT) with hematopoietic stem cell reinfusion (ASCT) was delivered to 35.5% of patients. With a median follow-up of 9 years, 10-year FFS was 57% (95% Confidence Interval CI: 33-75) and OS was 64% (95% CI: 41-80). In univariate analysis only age > 48 years was associated with an inferior FFS [44 % (95% CI:18-68) vs 92% (95% CI:54-99), p=<0.001] and OS [40% (95%CI:16-65) vs 100% , p=0.03]. There was no significant difference in the outcome of patients treated with HDCT+ASCT compared to those treated with conventional dose CT [FFS 75% (95%CI: 30-93) vs 63% (95%CI: 36-82), p=0.78; OS 71% (95%CI: 26-92) vs 64% (95%CI: 34-83),p=0.21].

Conclusions: This retrospective cohort of patients with late relapse HL is to date one of the largest case series and with the longest follow up. Besides the rarity of these cases, late relapse of HL appears to have a good prognosis. Classical prognostic scores for relapsed HL have no role in this setting. In the subgroup analyses, being older than 48 years conveys a worse prognosis. HDCT and ASCT does not appear to confer an important survival advantage over conventional dose CT.

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